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author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2013-11-14 14:31:13 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-15 09:32:15 +0900 |
commit | 09ef4939850aa81e3822b5dfb9ba2ada5e565816 (patch) | |
tree | 353dfb20ae393be66e1bc6ebc44b14a81a597cd2 | |
parent | 9491846fca57e9326b6673716c386b76fc13ebca (diff) | |
download | linux-09ef4939850aa81e3822b5dfb9ba2ada5e565816.tar.gz linux-09ef4939850aa81e3822b5dfb9ba2ada5e565816.tar.bz2 linux-09ef4939850aa81e3822b5dfb9ba2ada5e565816.zip |
x86: add missed pgtable_pmd_page_ctor/dtor calls for preallocated pmds
In split page table lock case, we embed spinlock_t into struct page.
For obvious reason, we don't want to increase size of struct page if
spinlock_t is too big, like with DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC or
on -rt kernel. So we disable split page table lock, if spinlock_t is
too big.
This patchset allows to allocate the lock dynamically if spinlock_t is
big. In this page->ptl is used to store pointer to spinlock instead of
spinlock itself. It costs additional cache line for indirect access,
but fix page fault scalability for multi-threaded applications.
LOCK_STAT depends on DEBUG_SPINLOCK, so on current kernel enabling
LOCK_STAT to analyse scalability issues breaks scalability. ;)
The patchset mostly fixes this. Results for ./thp_memscale -c 80 -b 512M
on 4-socket machine:
baseline, no CONFIG_LOCK_STAT: 9.115460703 seconds time elapsed
baseline, CONFIG_LOCK_STAT=y: 53.890567123 seconds time elapsed
patched, no CONFIG_LOCK_STAT: 8.852250368 seconds time elapsed
patched, CONFIG_LOCK_STAT=y: 11.069770759 seconds time elapsed
Patch count is scary, but most of them trivial. Overview:
Patches 1-4 Few bug fixes. No dependencies to other patches.
Probably should applied as soon as possible.
Patch 5 Changes signature of pgtable_page_ctor(). We will use it
for dynamic lock allocation, so it can fail.
Patches 6-8 Add missing constructor/destructor calls on few archs.
It's fixes NR_PAGETABLE accounting and prepare to use
split ptl.
Patches 9-33 Add pgtable_page_ctor() fail handling to all archs.
Patches 34 Finally adds support of dynamically-allocated page->pte.
Also contains documentation for split page table lock.
This patch (of 34):
I've missed that we preallocate few pmds on pgd_alloc() if X86_PAE
enabled. Let's add missed constructor/destructor calls.
I haven't noticed it during testing since prep_new_page() clears
page->mapping and therefore page->ptl. It's effectively equal to
spin_lock_init(&page->ptl).
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | arch/x86/mm/pgtable.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index dfa537a03be1..1a7d21342e02 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -189,8 +189,10 @@ static void free_pmds(pmd_t *pmds[]) int i; for(i = 0; i < PREALLOCATED_PMDS; i++) - if (pmds[i]) + if (pmds[i]) { + pgtable_pmd_page_dtor(virt_to_page(pmds[i])); free_page((unsigned long)pmds[i]); + } } static int preallocate_pmds(pmd_t *pmds[]) @@ -200,8 +202,13 @@ static int preallocate_pmds(pmd_t *pmds[]) for(i = 0; i < PREALLOCATED_PMDS; i++) { pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP); - if (pmd == NULL) + if (!pmd) + failed = true; + if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) { + free_page((unsigned long)pmds[i]); + pmd = NULL; failed = true; + } pmds[i] = pmd; } |